Sunday in Philadelphia

I'll be going to Philadelphia for the day (a Sunday, soon) with two adults and three kids (7-13 years old and adventurous eaters). I'm wondering if there's some thing or some place that's a must to try. Could be the best cheese steaks. Could be ethnic. Could be lunch or dinner. Should be casual and fun. Any ideas would be welcome. Thanks.

Pat's Steaks (or Pat's King of Steaks) is always an option under these circumstances. Very greasy, very delicious. I am of the opinion that cheez wiz is the way to go; provolone makes a lot of conceptual sense, but it doesn't melt enough for me to prefer it. I highly recommend the pizza steak. The red sauce is, surprisingly, of as high a quality as you would expect in a nice family owned southern Italian restaurant. Extremely tasty.

If you come in early in the morning, I cannot urge you strongly enough to breakfast at the Morning Glory Diner. Fresh, high quality diner food -- the best pancakes and biscuits I've ever had. And the frittatas are a wonderful alternative to the omelette. I love this place; whenever my girlfriend is in town, this is a definite stop.